chore: clean up migration files and update CLAUDE.md documentation

- Consolidate migration numbering (move full_bas_2026 to slot 044)
- Remove dead/superseded migrations (document_matching, reversal columns)
- Update CLAUDE.md with placeholder migration notes and corrected descriptions
- Fix migration SQL for invoice_inbox, extension_data, supplier_invoices

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

supabase/migrations/20240101000034_fix_extension_data_trigger.sql

@@ -1,19 +1,18 @@
 -- Migration 034: Fix extension_data updated_at trigger
--- The original trigger references update_updated_at() which does not exist.
--- The correct function is public.update_updated_at_column().
--- Wrapped in DO block in case extension_data table does not yet exist.
+-- Originally fixed a wrong function reference (update_updated_at vs update_updated_at_column).
+-- The issue is now fixed directly in migration 020, making this a no-op for fresh deployments.
+-- Kept for migration numbering sequence. Safe to re-run: just drops a trigger that may not exist.
 
-do $$
-begin
-  if exists (
-    select 1 from information_schema.tables
-    where table_schema = 'public' and table_name = 'extension_data'
-  ) then
-    drop trigger if exists extension_data_updated_at on public.extension_data;
-
-    create trigger extension_data_updated_at
-      before update on public.extension_data
-      for each row execute function public.update_updated_at_column();
-  end if;
-end;
+DO $$
+BEGIN
+  -- Drop the incorrectly-named trigger if it exists from an older migration version
+  IF EXISTS (
+    SELECT 1 FROM information_schema.triggers
+    WHERE trigger_schema = 'public'
+      AND event_object_table = 'extension_data'
+      AND trigger_name = 'extension_data_updated_at'
+  ) THEN
+    DROP TRIGGER extension_data_updated_at ON public.extension_data;
+  END IF;
+END;
 $$;